Deal with some old DBase application that don't (cannot) enforce referential integrity and you know why you should always use them. Even today there are modern samples of this and usually they...

This site http://www.spywarewarrior.com/rogue_anti-spyware.htm reports GIANT Companies/Microsoft Anti-spyware as respectable and probable capable to do the job.

But why not use the famous two: Ad-aware and Spybot S&D?